Takadanobaba Livestreamer Murder: Fiancée’s Heartbreaking Confession—“The Modest but Happy Days with Ai Mogami” [Exclusive]

The “Last Conversation” on the Day of the Tragedy

On the morning of the incident, Airi Sato (known online as “Ai Mogami,” aged 22), a livestreamer, reportedly left her home as usual.

“I think it was around 7:00 a.m. It was raining and cold that day, so she asked me about her outfit, saying, ‘Will I be cold in this?’ I had just woken up and hadn’t even put my contact lenses in yet, so I looked at her through blurry eyes and replied, ‘I think you’ll be fine.’”

That was the last conversation between Airi and her fiancé, Daiken Yui (34).

In March 2025, a horrific incident occurred on the streets of Takadanobaba when Ms. Sato, who was livestreaming, was stabbed to death with a knife by defendant Kenichi Takano (44), and her agonizing final moments were broadcast live.

Airi was active as a streamer on platforms such as the streaming app “Fuwatch.” She met the defendant, Kenichi Takano, through streaming and the two grew close. Financial disputes arose after she accepted large sums of money from Takano, whose romantic feelings for her had intensified. This became the motive for the crime.

In July of this year, the Tokyo District Court sentenced Takano to 16 years in prison (he later appealed). For the first time, Mr. Yui has recounted the entire story—from his first meeting with Airi to their breakup.

Around 9:00 a.m. on the day of the incident, Airi began a live stream near Shinjuku Station. Mr. Yui was on the move while watching her stream. Airi was walking from Shinjuku to Shin-Okubo and Takadanobaba as part of a project called “Live Stream Around the Yamanote Line,” and was just about to head back toward Shin-Okubo when it happened.

“Suddenly, Mogami (Airi) said, ‘Wait, no way?’ and immediately afterward, I heard a scream: ‘Eek!’ I think that’s probably when she dropped her smartphone. She couldn’t see anything anymore, and after I heard her say, ‘Help, help, help…’ for the last time, I couldn’t hear anything else.”

Sensing something was wrong, Mr. Yui immediately called 110 and 119. A few minutes later, something appeared on the screen.

“I saw her, covered in blood and mangled. At that moment, I braced myself, thinking, ‘She probably won’t make it.’ After that, I heard a sound like something hitting something. It wasn’t until much later that I realized it was the sound of Defendant Takano kicking the body.”

Mr. Yui immediately headed to the hospital where Airi had been taken.

“I think it was around 12:00 p.m. A detective and a doctor came and told me, ‘Airi Sato’s death was confirmed at 11:10 a.m.’ From there, I went to the Totsuka Police Station, where I was questioned in detail about the timeline of events—from my first meeting with Mogami to the incident itself. They also asked me about her bank accounts, which I didn’t know about.”

The Reason Behind Their “Non-Interfering” Living Arrangement

The two met in June 2023. It all started with “WePlay,” an app that lets users enjoy various games while using voice chat.

“I had a ‘room’ (a social space) open on the app, and Saigami started joining it. We got to know each other better as we chatted back and forth a few times. Users on the app are ranked based on how much they spend, and I think she was at ‘V7’—a rank you can’t reach unless you spend about 5 million yen.”

They continued chatting online and met in person for the first time in July of that same year.

“When we actually met, she turned out to be a smart, talkative woman. Rather than one of us explicitly confessing our feelings, we just naturally started dating.”

Their relationship began immediately. They started living together in “a quiet neighborhood in Tokyo” (Mr. Yui).

In September, about two months into their relationship, Mr. Yui collapsed due to cluster headaches and was unable to work. During that time, she stayed by his side and supported him constantly, leading Mr. Yui to realize, “I can’t do this without her.” On October 24, 2023, Airi’s birthday, he proposed to her.

“I told her, ‘Will you marry me?’ on WePlay. She replied, ‘Yes, I’d love to.’”

The two weren’t the kind of couple who were “together 24/7”; instead, they lived together while maintaining their independence and avoiding deep interference in each other’s lives.

“We talked a lot about work and our future. I even advised her that it might be better to make money through social media rather than working in the wedding industry. We’d watch YouTube together and say things like, ‘How does this person get such high view counts?’ or ‘This person is amazing.’ We had conversations like that all the time.”

Mr. Yui believes they adopted this hands-off approach because “we both had distant relationships with our families.” Airi had told him she had grown up in a children’s home.

“We were engaged, but I’ve never actually met her immediate family. I haven’t seen them even after she passed away. As for the wedding, we hadn’t set a specific date. We didn’t have a concrete plan for the future, like ‘Let’s do this in X years,’ but we did want children. She also said she loved kids.

We both felt we’d finally found a family, and we’d say to each other, ‘It would be nice if we could stay together forever.’ When I’d finish work and come home, Mogami would be there. It was a simple life, but that was happiness to me.I hadn’t really had the experience of ‘someone being home when I got back.’ When I was bedridden at Christmas, she made a huge spread for me—pasta, cake, salad, and all sorts of things. She was a great cook, too.”

It was around November 2023 that defendant Takano entered their lives. The money defendant Takano had lent to Airi totaled approximately 2.55 million yen, and he had filed a civil lawsuit demanding repayment—

In the “FRIDAY November 13 & 20 Issue” released on October 30 and the paid version “FRIDAY GOLD,” the magazine provides a detailed account—accompanied by photos—of why Mr. Yui was drawn to Airi,her phone calls with Defendant Takano, how she contemplated suicide after being subjected to slander and abuse from all over Japan following the incident, and her reasons for becoming a livestreamer herself—all accompanied by photographs.

Click here to view the full details and multiple photos ↓↓

From the November 13 & 20, 2026, combined issue of *FRIDAY*